Different methods are compared for the preservation of a Rhizomucor mi
ehei strain used for the production of rennet, which is used in the da
iry industry. The best method was found to be preservation under miner
al oil. After 2 years of storage, R. miehei kept its original milk clo
tting activity, had a lowered non-specific proteolytic activity and th
erefore a higher specific activity.